Electrically Switchable Circularly Polarized Light Detection in Optically Active Ferroelectric

ABSTRACT Circularly polarized light (CPL) detection is fundamental to advanced photonic and optoelectronic technologies, yet electrically reversible control of CPL selectivity remains a critical challenge. Optically active ferroelectrics are uniquely suited to address this challenge because they integrate symmetry‐enabled optical activity, switchable spontaneous polarization, and the bulk photovoltaic effect (BPVE) within a single material platform. Herein, we report an optically active hybrid perovskite ferroelectric, BnA 2 MA 2 Pb 3 Br 10 ( 1 ; BnA is 3‐butenylammonium, MA is methylammonium), in which electrically switchable CPL detection is successfully achieved. Leveraging the BPVE in 1 , the device exhibits highly sensitive self‐powered CPL detection, with an anisotropy factor of up to 0.62. More importantly, ferroelectric polarization reversal reverses the CPL selectivity, enabling electrically reconfigurable CPL detection. This work establishes optically active ferroelectrics as a viable platform for electrically reconfigurable self‐powered chiroptoelectronic devices.